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Date: Fri, 17 Feb 2012 13:33:27 -0500 (EST)
Message-Id: <20120217.133327.1178765872497293871.davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: alex.shi@intel.com, linux-kernel@vger.kernel.org, tim.c.chen@intel.com,
        ying.huang@intel.com, netdev@vger.kernel.org
Subject: Re: TCP_STREAM performance regression on commit b3613118
From: David Miller <davem@davemloft.net>
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From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 17 Feb 2012 10:50:39 +0100

> Le vendredi 17 février 2012 à 16:18 +0800, Alex,Shi a écrit :
>> The tcp_stream loop back performance has about 10% drop on the
>> commitment on our core2 2 sockets server. This commit has 2
>> parents(7505afe28, 5983fe), but both of them have no regression. So
>> guess the impact just happened when this 2 parents joint. That beyond
>> our capability to dig it more.
>> 
>> Any ideas? 
> 
> Most probably the more accurate truesize determination is responsible of
> this tcp regression, since some prior assumptions might be wrong.
> 
> Want to give more information on the workload ?
> Is it a 32 or 64 bit kernel ?

And let's start CC:'ing netdev too.